Toxic
by FosterStinson
Summary: After the Joker abandons Harley to move on to his "bigger and better" plan, she enlists the help of her best friend, Poison Ivy, to get her revenge, only to discover that there is more to their friendship than she previously thought. Slow burn. Guest appearances from various DC Characters, none of which I own.
1. No Man Will Ever Hurt Me Again

_21 Years Ago…_

An 11-year-old Pamela Isley sat in her worn down room playing with her chemistry set. She was happy. She knew it was too good to last. Her door swung open to reveal her father, seemingly more drunk than usual.

"What the hell are you doing in here?" he slurred.

"Nothing daddy." She answered the same answer she always gives him.

He stood there and stared at her.

"Where'd you get this?" he asked, picking up the chemistry set. She flinched.

"Mommy got it for me."

He studied it intensely.

"How much was it?"

"I don't know daddy."

He threw it into the wall, shattering it. Pamela got out of her chair and screamed. Her mother came running in.

"Richard!"

She was immediately met with a backhand, knocking her to the ground. Tears were in Pamela's eyes.

"Daddy please!"

"You stay out of this!" he said, pointing at her intensely. She cowered further into her bed. "Get up, Lois!" he screamed, yanking her up by her hair. She wept in pain, tears falling down her cheeks. Pamela watched from the sidelines as her father began hitting her mother once more. She cried. And she cried. And she cried. Then she heard something snap. Maybe it was one of her mother's bones. Maybe it was something in the back of her mind. She charged at her father, screaming, angrier than she'd ever been in her life. She was going to save her mother.

She was met with the back of her father's hand across her face, which was followed by her hitting the wall.

 _Present Day…_

Poison Ivy hit the wall with a thud after being kicked in the stomach by Batgirl.

"Remind me never to pull a heist with you again!" she screamed at Catwoman, who was sparring, more like dancing, with Batman.

"Oh come on! You know we can still pull this off!" Selina retorted.

"Yeah, right." Ivy muttered under her breath as she forced a giant vine to rip itself out of the ground and wrap around Batgirl, lifting her up into the air.

"Batgirl!" shouted Batman.

"I got her!" said the ever-cheerful Nightwing, leaping into the building from the hole in the skylight that Catwoman had cut earlier. He landed on the vine and pulled out a bottle that was probably labeled "Bat-Freeze".

"What are you doing here?" asked Batgirl as Nightwing shook the Bat-Freeze.

"I got Batman's distress call. Don't worry, I'll have you out in a flash." However, before he could spray it he, too, was hit with a vine that had been conjured up by Ivy. He hit the wall and dropped the Bat-Freeze.

Ivy couldn't help but smirk as she ran passed the battle between Batman and Catwoman to grab the bag of jewels that Selina had wanted to steal. She was about to leave, but stopped herself. _Honor among thieves_ she thought with a sigh.

"Catwoman! Let's go!"

"I'm a little busy!" she said, dodging a punch thrown by Batman. "I'll meet you at the rendezvous, just get out of here!"

Obliging, Ivy ran outside. However, she was immediately punched in the face by Black Canary, which knocked her to the ground hard. She lost her grip on the bag and with Canary standing over her, she knew it was over.

"Good to see you, Pam." She barely heard Canary saying as she blacked out.

Soon enough she was being escorted through the halls of Arkham Asylum by Batman. It came as no surprise to her that Selina had escaped with the bag Ivy had lost. After being put in her cell, she quickly huddled in one corner and shut out reality, counting down the seconds to her inevitable escape.

However she found her mind wandering.

 _I wonder if Harley's here._

She hadn't seen Harley in a few months ever since she and Joker supposedly took a vacation to Santa Prisca. Word was that they were back in Gotham. God, Ivy wanted to see her.

 _I hope she's okay._


	2. Change of Heart

_11 Years Ago…_

A 17-Year-Old Harleen Quinzel comes rushing in through her front door excitedly. Her father is sitting in his favorite recliner reading the newspaper and her mother is nursing Harleen's baby brother while watching her favorite soap opera.

"Mom! Dad! I got accepted into Wayne University!" she exclaimed, waving her acceptance letter around.

"That's wonderful, honey." Muttered her father monotonously, not even looking up at her.

"Sweetie, if you could be a little more quiet, you'll upset Phillip." Said her mother.

"But-"

"Listen to your mother, Harleen."

"Thank you, Thomas."

"You're welcome, Frances."

Harleen stood there, defeated. Swallowing her pride, she stuck the acceptance letter in her pocket and walked up to her room. She knew someone who would be happy for her. She got onto her computer and emailed Professor Hugo Strange, a famous psychiatrist who she had reached out to before. He'd promised her that she had a bright future ahead of her.

 _Present Day…_

Harley had to cover her eyes to shield them from the brightness of the sparks.

"Whatcha doin' Mistah J?" she asked.

"Quiet, Harley!" he shouted. "I'm almost finished."

She walked up to him and pulled his jacket off quickly.

"Don't you wanna take a little break and rev up your Harley?"

He looked back at her and grinned. He leaned in as if he was going to kiss her, but he instead placed his hand on her face and shoved her backwards, causing her to land on her butt. She pouted.

"Oh don't be like that Harley! This is the trap that will finally kill Batman! Then we'll be free to rule Gotham with nothing in our way."

"But what about Robin? And Batgirl? And Nightwing? And the other Robin? And-"

"Do you seriously think any of them could possibly stand up to _me_?" he asked menacingly. She gulped and shook her head. Joker then returned to his work.

The next day the two of them and their gang of clowns had successfully pulled off a generic heist in order to get Batman's attention. Which it did.

He was in pursuit in the Batmobile as he followed them back to their hideout. Once there, he was ambushed by Joker's new hired muscle, who was decked out with Venom, which Joker had stolen during their vacation in Santa Prisca.

Batman woke up upside down, chained to the inside of a coffin, which was hanging on a thin rope above a vat of the same chemical that turned the Joker into what he is now. The chemical on its own wouldn't kill Batman, but the acid which the Joker added to the mix certainly would. There were mechanical teeth chewing on the rope as the Joker was boasting.

"This is the end of the line, Bats. I always thought that we'd go out in a grand slam with thousands of lives on the line as well. I saw a school bus in the mix somewhere. But oh well. I've moved on to bigger and better things, so this'll have to do." All of a sudden, his watch started beeping. Joker looked at it and grinned. He looked at the discount Bane and held his hand out. He handed Batman's utility belt to the Joker, who immediately put it on. "What do you think? Does it clash with the suit?"

Batman remained silent.

"I'll take that as a no. Well, Bats, I'd love to stay and watch the skin melt off your face, but I have places to be and people to kill. Harley! Stay here and make sure the Bat eats it."

"Sure thing, puddin!" she said enthusiastically as he left without another word. After the door slammed shut it was just Harley and Batman. The only sound was the chattering teeth eating away at the rope. Harley turned to face him.

"Gee, you're really in it this time, B-Man."

"I don't suppose there's a chance you'll give me a hand?" he asked, challenging her.

"Pfft, what are you on, Bats?"

"That's quite a large gash on your cheek." This took her off guard. "It probably needs stitches."

She looked away and rubbed her arm.

A large portion of the rope was destroyed, causing the coffin to lurch downward. Harley looked over at him, the stone look on his face always present. She gulped. It lurched again. Nervously, Harley grabbed an axe from the Joker's weapons chest and slammed it into the vat, causing it all to come pouring out. She yelped as it almost touched her and she ran into the corner as it began burning the ground. The last of it exited the vat right as the coffin fell in. Harley ran over to find Batman face up, barely conscious from the fall. She hopped in and pulled out a bobby pin to open his chains. As she pulled him up he took a deep breath and looked her in the eyes.

"Thank you, Harley."

"Mistah J's gonna kill me."

Then, sirens started wailing.

"You called the cops?! I saved your life!" she screamed, getting out of the vat angrily.

"I didn't call them." He said calmly as he climbed out as well.

"You don't mean?"

Batman nodded. The Joker had framed Harley.

"I can help you if you tell me everything I want to know."

Reluctantly, Harley nodded.


End file.
